Re: [PATCH 3/4] OMAPDSS: panel-sharp-ls037v7dw01: add device tree support

* Tomi Valkeinen [off-list ref] [140507 09:03]:

On 07/05/14 18:03, Tony Lindgren wrote:

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+	lcd0: display {
+		compatible = "sharp,ls037v7dw01";
+		power-supply = <&lcd_3v3>;
+		reset-gpios = <&gpio5 27 GPIO_ACTIVE_HIGH>;	/* gpio155, lcd RESB */
+		enable-gpios = <&gpio5 26 GPIO_ACTIVE_HIGH	/* gpio154, lcd MO */
+				&gpio1 2 GPIO_ACTIVE_HIGH	/* gpio2, lcd LR */
+				&gpio1 3 GPIO_ACTIVE_HIGH	/* gpio3, lcd UD */
+				&gpio5 24 GPIO_ACTIVE_HIGH>;	/* gpio152, lcd INI */

Why are most of the gpios in 'enable-gpios'? MO, LR and UD don't really
have anything to do with enabling the panel. Why not just have one
'gpios' array with all the gpios, as they are quite a mixed bunch?

Yeah that's what I had initially, but reading simple-panel.txt noticed
there are some standardized GPIOs for reset and enable.

I'm not sure if it's worth to try to make it compatible with
simple-panel. simple-panel bindings do not work with omapdss anyway, and
simple-panel doesn't have the support for input ports/endpoints.

Can the panel be used with only one gpio (I guess that would be INI or
RESB)? If not, simple-panel doesn't work.

I guess in theory yes.
 

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How about we set up one reset-gpios, one enable-gpios and an array of
three unlabelled GPIOs?

Or if we want to add something generic, we could add new mode-gpios
property that other panels might be able to use too?

BTW, I'm also personally fine with all five gpios showing in a single
gpios property, I'm not too exited about naming anything in DT..

I don't have a strong opinion here. I don't have much experience with
DT, especially with making bindings compatible with other ones.

I'd just forget the simple-panel, and have single gpio array.

Well if it's a don't care flag for both of us, let's try to use
the existing standard for simple-panel.txt and add mode-gpios
property. I'll post a patch for that.

Regards,

Tony